But not on this particular SoC. Qualcomm (with Apple and Samsung not terribly close behind) remains the volume king even in China, last I checked. This other small-vendor SoC's are gaining momentum, but they're not there yet.
The reality today is that MediaTek is number two in mobile after Qualcomm. Meizu MX5 uses a MediaTek SoC as does the new Xiaomi Redmi Note 2 and many others.